This invention relates to a fluid supply system which provides supply pressure regulation and particularly, to such a system adapted to deliver high viscosity fluids such as sealant materials to a dispensing apparatus.
During assembly of motor vehicle body components and other devices, it is frequently necessary to apply beads of high viscosity fluids such as sealants which are often placed within body component seams and other locations to provide sound deadening, bonding, and/or corrosion resistance. These substances are either dispensed manually by an operator or by automated dispensing guns. In order to properly dispense such materials, very great supply pressures are required. Fluid supply systems for such applications are presently known. These devices, however, suffer a significant shortcoming in that they are unable to regulate the pressure at which the fluid is supplied to within a narrow range. Instead, significant fluid pressure fluctuations occur which can lead to inexact fluid dispensing metering. Moreover, the physical characteristics of some fluids such as certain industrial sealants are known to change significantly in response to variations in their hydrostatic pressure. Some of these substances undergo substantial viscosity changes with applied pressure which further aggravates metering consistency problems, and can further lead to sealant sputtering and plugging.
In addition to controlling fluid pressure in a fluid supply system used for dispensing sealants and other materials, it is further desirable to provide such an apparatus with a dual supply of fluids, thereby enabling replenishment of one supply while another is drawn. Such dual fluid supplies permit the device to operate continuously without interruption despite depletion of one fluid supply.
In view of the above, it is a principal object of this invention to provide a fluid supply system capable of supplying high viscosity fluids at supply pressures which are maintained within a desired range of pressures. It is a further object to enable the range of supply pressure to be adjustable. It is a further object of this invention to provide such a system which is capable of drawing fluid from two or more fluid reservoirs and which automatically switches to an alternate fluid source when one becomes depleted. It is yet another object of this invention to provide a system overcoming the previously-metioned shortcomings according to the prior art which may be constructed from readily available components.